2003 Pontiac Montana TRANSMISSION FLUID SPILL ON THE ENGINE

2003 Pontiac Montana 6 cyl Front Wheel Drive Automatic

Transmission fluid spilled all over the van engine as the transmission fluid being changed by the mechanic shop.

I noticed the check engine light was flashing and the tempreture gage was at high and the light was on.

Is there an serious damage done to the engine or is it a simple fix.

What can be done to fix the problem. I feel unsafe driving the van.

Thank you
Roxanne